The go ahead and consider that it's time to remove the player and get it on a bench to get inside.

https://www.google.com/search?q=how+to+remove+a+stuck+cassette+tape has a lot more ideas.

Here I went all the way and replaced my player for a modern (?) unit with just CD/DVD/MP3/Bluetooth and such. My car has only 55K miles on it but 18 years old so it wasn't a hard decision.